In July, my son lost all of his recorded shows when his box overheated. It was in a case behind a closed door. I checked my box and noticed it was hot. As a temporary measure, I put two pieces of wood on it to raise the DVD player.
When the warranty period on my computer expired I recycled the box. The two pieces of foam in the box were black. I trimmed them to fit the area and put the DVD player in the grooves. I placed the box on top. Now the air can circulate around the top and bottom of each device.